Light emitting element and fabricating method thereof

ABSTRACT

A fabricating method of light emitting element. A substrate is provided. A plurality of first concaves and a plurality of second concaves are formed on the substrate, wherein a volume of each first concave is different from a volume of each second concave. A plurality of first light emitting diode chips and a plurality of second light emitting diode chips are provided, wherein a volume of each first light emitting diode chip is corresponding to the volume of each first concave, and a volume of each second light emitting diode chip is corresponding to the volume of each second concave. The first light emitting diode chips are moved onto the substrate such that the first light emitting diode chips go into the first concaves, and the second light emitting diode chips are moved onto the substrate such that the second light emitting diode chips go into the first concaves.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefits of U.S. provisionalapplication Ser. No. 61/599,955, filed on Feb. 17, 2012. The entirety ofthe above-mentioned patent applications is hereby incorporated byreference herein and made a part of this specification.

BACKGROUND

1. Technical Field

The technical field relates to a light emitting element and afabricating method thereof, and more particularly, to a light emittingdiode (LED) light emitting element and a fabricating method thereof.

2. Background

A self-luminous display technology is a display technology that usesred, green and blue light emitting diode chips as display pixels, andhas features of energy-saving, high contrast, wide color gamut, vividcolor and fast response time; therefore, more and more electronicdevices (such as TV) are using the light emitting diodes ofself-luminous display technology.

With different materials and growth conditions, the red, green and bluelight-emitting diodes are not easily to be grown on a same substrate forforming display pixel arrays, and thus after fabrications of the red,green and blue light-emitting diodes are completed, chips aretransferred onto a display driving substrate, such as a thin filmtransistor (TFT) backplane. However, following a refinement of thedisplay pixels and an enhancement of resolution, the fabricating methodfor transferring the chips has already faced a bottleneck ofinsufficient throughput. As such, how to increase the throughput of thepixel arrays in response to the refinement of the display pixels and theenhancement of the resolution is substantially an important topic ofcurrent light emitting diode self-luminous display devices.

SUMMARY

A light emitting element and a fabricating method thereof are provided,such that the throughput of the light emitting element is improved.

The fabricating method of the light emitting element includes thefollowing steps. A substrate is provided. A plurality of first concavesand a plurality of second concaves are formed on the substrate, whereina volume of each first concave is different from a volume of each secondconcave. A plurality of first light emitting diode chips and a pluralityof second light emitting diode chips are provided, wherein a volume ofeach first light emitting diode chip is corresponded to the volume ofeach first concave, and a volume of each second light emitting diodechip is corresponded to the volume of each second concave. The firstlight emitting diode chips are moved onto the substrate so that thefirst light emitting diode chips go into the first concaves, and thesecond light emitting diode chips are moved onto the substrate so thatthe second light emitting diode chips go into the second concaves.

In an embodiment, a shape of each first concave is different from ashape of each second concave.

The light emitting element includes a substrate, a plurality of firstlight emitting diode chips and a plurality of second light emittingdiode chips. The substrate has a plurality of first concaves and aplurality of second concaves, wherein a volume of each first concave isdifferent from a volume of each second concave. A volume of each firstlight emitting diode chip is corresponded to the volume of each firstconcave. The first light emitting diode chips are located within thefirst concaves. A volume of each second light emitting diode chip iscorresponded to the volume of each second concave. The second lightemitting diode chips are located within the second concaves.

In an embodiment, a shape of each first concave is different from ashape of each second concave.

Several exemplary embodiments accompanied with figures are described indetail below to further describe the disclosure in details.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide further understanding,and are incorporated in and constitute a part of this specification. Thedrawings illustrate exemplary embodiments and, together with thedescription, serve to explain the principles of the disclosure.

FIG. 1A to FIG. 1F are flow diagrams illustrating a fabricating methodof a light emitting element according to an exemplary embodiment.

FIG. 2 and FIG. 3 are respectively schematic diagrams illustrating asubstrate and a plurality of light emitting diode chips according toanother exemplary embodiment.

FIG. 4 is a partial cross sectional view of the light emitting elementof FIG. 1F.

FIG. 5 is a partial cross sectional view of the light emitting elementof FIG. 2.

FIG. 6 is a top view of the light emitting element of FIG. 5.

FIG. 7 is a partial cross sectional view of a substrate according toanother exemplary embodiment.

FIG. 8 illustrates a light emitting diode chip corresponded to a concaveof FIG. 7.

FIG. 9 is a partial cross sectional view illustrating a light emittingelement according to another exemplary embodiment.

FIG. 10 is a top view of the light emitting element of FIG. 9.

FIG. 11 is a partial enlarged diagram of a plurality of first lightemitting diode chips of FIG. 9.

FIG. 12A to FIG. 12F are flow diagrams illustrating a fabricating methodof a light emitting element according to another exemplary embodiment.

FIG. 13A to FIG. 13E are flow diagrams illustrating a fabricating methodof a light emitting element according to yet another exemplaryembodiment.

FIG. 14 is a top view of the light emitting element of FIG. 13E.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

FIG. 1A to FIG. 1F are flow diagrams illustrating a fabricating methodof a light emitting element according to an exemplary embodiment.Firstly, as depicted in FIG. 1A, a substrate 110 is provided. Next, asdepicted in FIG. 1B, a plurality of first concaves 110 a, a plurality ofsecond concaves 110 b and a plurality of third concaves 110 c are formedon the substrate 110, wherein a volume and a shape of each first concave110 a are different from a volume and a shape of each second concave 110b, and a volume and a shape of each third concave 110 c are differentfrom the volume and the shape of each first concave 110 a and the volumeand the shape of each second concave 110 b. In FIG. 1B, only six firstconcaves 110 a, six second concaves 110 b and six third concaves 110 care illustrated, however, they have only been taken as an example;substantially, the first concaves 110 a, the second concaves 110 b andthe third concaves 110 c may be much more in numbers.

As depicted in FIG. 1C, a plurality of first light emitting diode chips120, a plurality of second light emitting diode chips 130 and aplurality of third light emitting diode chips 140 are provided, whereina volume and a shape of each first light emitting diode chip 120 arecorresponded to the volume an the shape of each first concave 110 a, avolume and a shape of each second light emitting diode chip 130 arecorresponded to the volume and the shape of each second concave 110 b,and a volume and a shape of each third light emitting diode chip 140 arecorresponded to the volume and the shape of third concave 110 c. Eachfirst light emitting diode chip 120, each second light emitting diodechip 130 and each third light emitting diode chips 140 of presentembodiment, for example, are respectively a red light emitting diodechip, a blue light emitting diode chip and a green light emitting diodechip. In other embodiments, each first light emitting diode chip 120,each second light emitting diode chip 130 and each third light emittingdiode chip 140 may respectively be the red light emitting diode chip,the green light emitting diode chip and the blue light emitting diodechip, or respectively be the blue light emitting diode chip, the redlight emitting diode chip and the green light emitting diode chip, orrespectively be the blue light emitting diode chip, the green lightemitting diode chip and the red light emitting diode chip, orrespectively be the green light emitting diode chip, the red lightemitting diode chip and the blue light emitting diode chip, orrespectively be the green light emitting diode chip, the blue lightemitting diode chip and the red light emitting diode chip, but thedisclosure is not limited thereto. For a more concise description, onlya first light emitting diode chip 120, a second light emitting diodechip 130 and a third light emitting diode chip 140 are illustrated inFIG. 1C, and are only taken as an example; substantially, the firstlight emitting diode chip 120, the second light emitting diode chip 130and the third light emitting diode chips 140 are more in numbers.

As depicted in FIG. 1D, the first light emitting diode chips 120 aremoved onto the substrate 110 so that the first light emitting diodechips 120 go into the first concaves 110 a. As depicted in FIG. 1E, thesecond light emitting diode chips 130 are moved onto the substrate 110so that the second light emitting diode chips 130 go into the secondconcaves 110 b. As depicted in FIG. 1F, the third light emitting diodechips 140 are moved onto the substrate 110 so that the third lightemitting diode chips 140 go into the third concaves 110 c, therebypartially completed the fabrication of the light emitting element 100.In the present embodiment, the first light emitting diode chips 120, thesecond light emitting diode chips 130 and the third light emitting diodechips 140, for example, are moved onto the substrate 110 by usingfluids, and in other embodiments, the light emitting diode chips may bemoved onto the substrate via other suitable methods, and the disclosureis not limited thereto.

In detail, in the present embodiment, each first concave 110 a, eachsecond concave 110 b and each third concave 110 c open at a surface 112of the substrate 110. A method of forming the first concaves 110 a, thesecond concaves 110 b and the third concaves 110 c includes thefollowing steps. A profile (illustrated as a circle in FIG. 1B) of eachfirst concave 110 a at the surface 112 is corresponded to a profile(illustrated as a circle in FIG. 1C) of a cross section of each firstlight emitting diode chip 120. A profile (illustrated as a rectangle inFIG. 1B) of each second concave 110 b at the surface 112 is correspondedto a profile (illustrated as a rectangle in FIG. 1C) of a cross sectionof each second light emitting diode chip 130 and different from theprofile of each first concave 110 a at the surface 112. A profile(illustrated as a triangle in FIG. 1B) of each third concave 110 c atthe surface 112 is corresponded to a profile (illustrated as a trianglein FIG. 1C) of a cross section of each third light emitting diode chip140 and different from the profile of each first concave 110 a at thesurface 112 and the profile of each second concave 110 b at the surface112. As a result, the first concaves 110 a, the second concaves 110 band the third concaves 110 c are enable to have shapes respectivelycorresponded to the first light emitting diode chips 120, the secondlight emitting diode chips 130 and the third light emitting diode chips140.

The aforementioned method is to fabricate the first concaves 110 a, thesecond concaves 110 b and the third concaves 110 c of different volumesand shapes on the substrate 110, and the volume and the shape of thefirst light emitting diode chips 120, the volume and the shape of thesecond light emitting diode chips 130 and the volume and the shape ofthe third light emitting diode chips 140 are respectively correspondedto the volume and the shape of the first concaves 110 a, the volume andthe shape of the second concaves 110 b and the volume and the shape ofthe third concaves 110 c. As a result, when the first light emittingdiode chips 120, the second light emitting diode chips 130 and the thirdlight emitting diode chips 140 are moved onto the substrate 110, thefirst light emitting diode chips 120 selectively go into the firstconcaves 110 a corresponded thereto, the second light emitting diodechips 130 selectively go into the second concaves 110 b correspondedthereto, and the third light emitting diode chips 140 selectively gointo the second concaves 110 c corresponded thereto, so as to enable thefirst light emitting diode chips 120, the second light emitting diodechips 130 and the third light emitting diode chips 140 to be quickly andcorrectly assembled onto the substrate 110 via an automatic alignmentmethod, and thus may effectively enhance a throughput of the lightemitting element 100.

The light emitting element 100 of the present embodiment, as illustratedin FIG. 1F, includes a substrate 110, a plurality of first lightemitting diode chips 120, a plurality of second light emitting diodechips 130 and a plurality of third light emitting diode chips 140. Thesubstrate 110 has a plurality of first concaves 110 a, a plurality ofsecond concaves 110 b and a plurality of third concaves 110 c, wherein avolume and a shape of each first concave 110 a are different from avolume and a shape of each second concave 110 b, and a volume and ashape of each third concave 110 c are different from the volume and theshape of each first concave 110 a and the volume and the shape of eachsecond concave 110 b. A volume and a shape of each first light emittingdiode chip 120 are corresponded to the volume and the shape of eachfirst concave 110 a. The first light emitting diode chips 120 arelocated within the first concaves 110 a. A volume and a shape of eachsecond light emitting diode chip 130 are corresponded to the volume andthe shape of each second concave 110 b. The second light emitting diodechips 130 are located within the second concaves 110 b. A volume and ashape of each third light emitting diode chip 140 are corresponded tothe volume and the shape of each third concave 110 c. The third lightemitting diode chips 140 are located within the third concaves 110 c.

The disclosure is not intended to limit the shapes of the concave andthe shapes of the light emitting diode chips on the substrate, andexamples accompanied with figures are provided below to further describethe disclosure. FIG. 2 and FIG. 3 are respectively schematic diagramsillustrating a substrate and a plurality of light emitting diode chipsaccording to another exemplary embodiment. Referring to FIG. 2, asubstrate 210 of the present embodiment has a plurality of firstconcaves 210 a, a plurality of second concaves 210 b and a plurality ofthird concaves 210 c, each first concave 210 a, each second concave 210b and each third concave 210 c are all trapezoids, and profiles of eachfirst concave 210 a, each second concave 210 b and each third concave210 c at a surface 216 of the substrate 210 are different from eachothers. Referring to FIG. 3, profiles of a first light emitting diodechip 220, a second light emitting diode chip 230 and a third lightemitting diode chip 240 of the present embodiment are all trapezoids andare respectively corresponded to the profiles of each first concave 210a, each second concave 210 b and each third concave 210 c. With this,the first light emitting diode chips 220, the second light emittingdiode chips 230 and the third light emitting diode chips 240 can bequickly, correctly and respectively assembled to the first concaves 210a, the second concaves 210 b and the third concaves 210 c on thesubstrate 210 via an automatic alignment method.

In detail, within the concaves of the substrate, there is a plurality ofelectrodes configured to electrically connect to the light emittingdiode chips corresponded thereof, and specific descriptions accompaniedwith figures are provided below. FIG. 4 is a partial cross sectionalview of the light emitting element of FIG. 1F. Referring to FIG. 4, thelight emitting diode chip (e.g., the first light emitting diode chip 120in FIG. 4) of the present embodiment has a positive electrode terminal122 and a negative electrode terminal 124, and a configuration of thelight emitting diode chip is a vertical type, such that the positiveelectrode terminal 122 is located within the concave (e.g., the firstconcave 110 a in FIG. 4) of the substrate 110 and electrically connectedto the substrate 110. The configuration of the light emitting diode chipmay also be a horizontal type, and examples accompanied with figures areprovided below to further describe the disclosure.

FIG. 5 is a partial cross sectional view of the light emitting elementof FIG. 2. FIG. 6 is a top view of the light emitting element of FIG. 5.Referring to FIG. 5 and FIG. 6, a configuration of light emitting diodechip (e.g., the first light emitting diode chips 220 in FIG. 5 and FIG.6) of the present embodiment is the horizontal type, such that apositive electrode terminal 222 and a negative electrode terminal 224are both located within the concave (e.g., the first concave 210 a inFIG. 5 and FIG. 6) of the substrate 210 and electrically connected tothe substrate 210.

Furthermore, shapes of the concaves of the substrate may be designed tobe asymmetric, so that the positive electrode terminal and the negativeelectrode terminal of the horizontally configured light emitting diodechip can automatically, correctly and respectively aligned to theelectrodes within the concaves; the following has taken the firstconcaves 210 a and the first light emitting diode chips 220 of FIG. 5and FIG. 6 as an example for the description. In a process offabricating the light emitting element, a first electrode 212 and asecond electrode 214 are respectively disposed at a first region A1 anda second region A2 within the first concaves 210 a of substrate 210,wherein a shape of the first region A1 is corresponded to the shape ofthe positive electrode terminal 222 of the first light emitting diodechip 220, and a shape of the second region A2 is corresponded to theshape of the negative electrode terminal 224 of the first light emittingdiode chips 220. The shape of the first region A1 is different from theshape of the second region A2, such that the shape of the first concave210 a is asymmetric. With this, the first light emitting diode chips 220is able to be automatically assembled to the first concave 210 a withcorrect direction, so that the positive electrode terminal 222 and thenegative electrode terminal 224 of the first light emitting diode chip220 may respectively and correctly be in contact with and electricallyconnect to the first electrode 212 and the second electrode 214. Thefollowing accompanied with figures describes other methods used forautomatically aligning the light emitting diode chips and the electrodeswithin the concaves.

FIG. 7 is a partial cross sectional view of a substrate according toanother exemplary embodiment. FIG. 8 illustrates a light emitting diodechip corresponded to a concave of FIG. 7. Referring to FIG. 7 and FIG.8, in the process of fabricating the light emitting element, a positiveelectrode pad 322 and a negative electrode pad 324 may be disposed at asurface 320 a of the light emitting diode chip (e.g., a first lightemitting diode chip 320 in FIG. 8), wherein one (illustrated with thenegative electrode pad 324) of the positive electrode pad 322 and thenegative electrode pad 324 is located at the geometric center of thesurface 320 a. In addition, a first electrode 312 is disposed at thegeometric center of a bottom surface 310 d of the concave (e.g., a firstconcave 310 a in FIG. 7) of the substrate 310, and a second electrode314 is disposed at the bottom surface 310 d, wherein the secondelectrode 314 appears to be in ring-shaped and symmetrically surroundsthe first electrode 312, and a distance D1 between the first electrode312 and the second electrode 314 equals or similar to a distance D2between the positive electrode pad 322 and the negative electrode pad324. With this, when the first light emitting diode chip 320 isassembled within the first concave 310 a, the positive electrode pad 322and the negative electrode pad 324 automatically and correctly alignedto the first electrode 312 and the second electrode 314, so that thefirst electrode 312 is electrically connected to one of the positiveelectrode pad 322 and the negative electrode pad 324, and the secondelectrode 314 is electrically connected to the another one of thepositive electrode pad 322 and the negative electrode pad 324. Moreover,positive and negative electrodes of periodically staggered arrangementmay also be disposed within the first concave of the substrate, whereina distance between the positive and negative electrodes is greater thana position offset of the first light emitting diode chip going withinthe first concave, such that when the positive and negative electrodeson the first light emitting diode chip go into the first concave, thepositive and negative electrodes is adapted to respectively contact thepositive and negative electrodes of periodically staggered arrangement,and thus achieve an effect of automatically aligning the light emittingdiode chip and the electrode within the concave.

The concaves mentioned in the above embodiments may all be formed withcambered surfaces, and reflective layers may be disposed within theconcaves so as to reflect lights emitted by the light emitting diodechips, and thereby enhance a light output efficiency of the lightemitting diode chips and enable the light emitting diode chips to have afavorable light output collimation. Further example accompanied withfigures is provided below to further describe the disclosure.

FIG. 9 is a partial cross sectional view illustrating a light emittingelement according to another exemplary embodiment. Referring to FIG. 9,a substrate 410 of the present embodiment has first concaves 410 a,second concaves 410 b and third concaves 410 c respectively configuredto accommodate first light emitting diode chips 420, second lightemitting diode chips 430 and third light emitting diode chips 440. For amore concise description, only one first concave 410 a, one secondconcave 410 b, one third concave 410 c, one first light emitting diodechip 420, one second light emitting diode chip 430 and one third lightemitting diode chip 440 are illustrated in FIG. 9; and substantially,amounts of the first concaves 410 a, the second concaves 410 b, thethird concaves 410 c, the first light emitting diode chips 420, thesecond light emitting diode chips 430 and the third light emitting diodechips 440 of the present embodiment, for example, are pluralities. Thefirst light emitting diode chips 420, the second light emitting diodechips 430 and the third light emitting diode chips 440, for example,respectively are red light emitting diode chips, blue light emittingdiode chips and green light emitting diode chips. In a process offorming the first concave 410 a, the second concave 410 b and the thirdconcaves 410 c, as depicted in FIG. 9, an inner wall of the firstconcaves 410 a, inner wall of the second concave 410 b and inner wall ofthe third concave 410 c are formed into cambered surfaces, and areflective layer 450, a reflective layer 460 and a reflective layer 470are respectively formed at the inner wall of the first concave 410 a,the inner wall of the second concave 410 b and the inner wall of thethird concave 410 c. By adjusting a curvature of the inner wall of thefirst concave 410 a, a curvature of the inner wall of the second concave410 b and a curvature of the inner wall of the third concave 410 c,light emitted by the first light emitting diode chip 420, the secondlight emitting diode chip 430 and the third light emitting diode chip440, through reflections of the reflective layer 450, the reflectivelayer 460 and the reflective layer 470, have a favorable light outputcollimation and light output efficiency.

In a process of fabricating the light emitting element, an electrode 480a, an electrode 480 b and an electrode 480 c may be disposed within thefirst concave 410 a, the second concave 410 b and the third concave 410c, and the electrode 480 a, the electrode 480 b and the electrode 480 care respectively configured to be electrically connected to the firstlight emitting diode chip 420, the second light emitting diode chip 430and the third light emitting diode chip 440. In addition, the reflectivelayer 450, the reflective layer 460 and the reflective layer 470 mayrespectively be electrically connected to the electrode 480 a, theelectrode 480 b and the electrode 480 c. With this, under a conditionwhen the light emitting diode chip (the first light emitting diode chip420, the second light emitting diode chip 430 o or the third lightemitting diode chips 440) is not really in contact with the electrode(the electrode 480 a, the electrode 480 b or the electrode 480 c), thelight emitting diode chip can smoothly be electrically connected to theelectrode through the contact of the light emitting diode chip (thefirst light emitting diode chip 420, the second light emitting diodechip 430 or the third light emitting diode chip 440) and the reflectivelayer (the reflective layer 450, the reflective layer 460 or thereflective layer 470).

FIG. 10 is a top view of the light emitting element of FIG. 9. Referringto FIG. 10, the first concave 410 a, the second concave 410 b and thethird concave 410 c of the present embodiment, for example, respectivelyhave cross sections of different profiles (respectively illustrated as arectangular cross section, a triangular cross section and a circularcross section), and shapes of the first light emitting diode chip 420,the second light emitting diode chip 430 and the third light emittingdiode chips 440 are respectively corresponded to the profiles of thefirst concave 410 a, the second concave 410 b and the third concaves 410c. As such, in the process of fabricating the light emitting element,the first light emitting diode chip 420, the second light emitting diodechip 430 and the third light emitting diode chip 440 can be quickly andcorrectly be assembled onto the substrate 410 via an automatic alignmentmethod. The blue light emitting diode chip and the green light emittingdiode chip generally have similar thicknesses, and the presentembodiment respectively corresponds the triangular concave (the secondconcave 410 b) and the circular concave (the third concave 410 c) ofhigher light extraction efficiencies to the blue light emitting diodechip (the second light emitting diode chip 430) and the green lightemitting diode chip (the third light emitting diode chip 440). Inaddition, a thickness of the red light emitting diode chip is generallygreater than the thickness of the blue light emitting diode chip and thethickness of the green light emitting diode chip; and therefore, asdepicted in FIG. 9, the first concave 410 a corresponded to the redlight emitting diode chip (the first light emitting diode chip 420) maybe formed into a deeper concave, the second concave 410 b correspondedto the blue light emitting diode chip (the second light emitting diodechip 430) and the third concave 410 c corresponded to the green lightemitting diode chip (the third light emitting diode chip 440) may beformed into shallower concaves, so as to further enhance an accuracy ofthe automatic alignment of the light emitting diode chips.

The electrode 480 a, the electrode 480 b and the electrode 480 cdepicted in FIG. 9 may respectively and selectively use differentmaterials to enable the electrode 480 a, the electrode 480 b and theelectrode 480 c to adapt to be soldered with different first solderingtemperature, second soldering temperature and third solderingtemperature. In the process of fabricating the light emitting element,when the light emitting diode chips are moved onto the substrate, if aportion of the light emitting diode chips go into concaves notcorresponded thereof, then differences in the soldering temperatures ofthe electrode 480 a, the electrode 480 b and the electrode 480 c may beused as a basis of assembly accuracy, and this is further described indetail below. For example, if a portion of the first light emittingdiode chips 420 correctly go into the first concaves 410 a correspondedthereof, and another portion of the first light emitting diode chips 420incorrectly go into the second concaves 410 b or third concaves 410 cthat is not corresponded thereof, then by using the first solderingtemperature to solder the electrode 480 a, the electrode 480 b and theelectrode 480 c, the first light emitting diode chip 420 currentlylocated within the first concave 410 a is combined to the electrode 480a via the soldering, and the first light emitting diode chip 420 locatedwithin the second concave 410 b or the third concave 410 c is notcombined to the electrode 480 b and the electrode 480 c and may beremoved. Next, the assembly of the light emitting diode chips arecontinued until all the first concaves 410 a are correctly assembledwith the first light emitting diode chips 420 corresponded thereof.Similarly, all the second concaves 410 b may be correctly assembled withthe second light emitting diode chips 430 corresponded thereof byapplying the second soldering temperature, and all the third concaves410 c may be correctly assembled with the third light emitting diodechips 440 corresponded thereof by applying the third solderingtemperature. As aforesaid, by using the differences between thesoldering temperatures of the electrode 480 a, the electrode 480 b andthe electrode 480 c as the basis of assembling the light emitting diodechips, the accuracy in the assembly may be enhanced and therebyenhancing the throughput.

FIG. 11 is a partial enlarged diagram of a plurality of first lightemitting diode chips of FIG. 9. Referring to FIG. 11, in the process offabricating the light emitting element, optical microstructures M may beformed on the first light emitting diode chip 420 so as to enhance thelight output efficiency. The second light emitting diode chip 430 andthe third light emitting diode chip 440 may also form the same orsimilar optical microstructures M for enhancing the light outputefficiency. The optical microstructures may be in an orderly array formor an irregular arrangement, the disclosure is not limited thereto. Forexample, the optical microstructures may be surface rougheningstructures, periodic micro-structures, periodic pore structures,periodic columnar structures or periodic cone structures.

Referring to FIG. 9, in the present embodiment, the first concave 410 ahas an opening terminal S1 and a bottom surface S2. In the process offabricating the light emitting element, as depicted in FIG. 9, the firstconcave 410 a may gradually shrink from the opening terminal S1 towardto the bottom surface S2, so that the first light emitting diode chip420 can smoothly go into the first concave 410 a, and the light emittedby the first light emitting diode chip 420 can indeed be reflected bythe reflective layer 450 on the inner wall of the first concave 410 a.The second concave 410 b and the third concave 410 c, may also asdepicted in FIG. 9, shrink from the opening terminal toward to thebottom surface, thereby achieving the same effect as described above. Inaddition, in the embodiment of FIG. 9, a size of the first concave 410 ais designed to be slightly greater than a size of the first lightemitting diode chip 420, so as to avoid the first light emitting diodechip 420 and the first concaves 410 a from being unable to besuccessfully assembled due to fabrication tolerances. The second concave410 b and the third concave 410 c, also as depicted in FIG. 9, aredesigned to be slightly greater than sizes of the second light emittingdiode chip 430 and the third light emitting diode chip 440, so that thesame effect as described above may be achieved.

FIG. 12A to FIG. 12F are flow diagrams illustrating a fabricating methodof a light emitting element according to another exemplary embodiment.Amounts of first light emitting diode chips 520, second light emittingdiode chips 530, third light emitting diode chips 540, first concaves510 a, second concaves 510 b and third concaves 510 c illustrated inFIG. 12A to FIG. 12F are only provided as an example, and in the otherembodiments, the amounts thereof are in greater numbers. Referring to alight emitting element 500 illustrated in FIG. 12F, a thickness of thefirst light emitting diode chips 520 thereof is greater than a thicknessof the second light emitting diode chips 530, and the thickness of thesecond light emitting diode chips 530 is greater than a thickness of thethird light emitting diode chips 540. In a fabrication process of thepresent embodiment, the first concaves 510 a, the second concaves 510 band the third concaves 510 c of the substrate 510 are fabricated asrespectively having different depths and are corresponded to the firstlight emitting diode chips 520, the second light emitting diode chips530 and the third light emitting diode chips 540 of differentthicknesses, so as to achieve an assembly effect of automaticallyaligning the light emitting diode chips, and this is further describedin detail below.

Firstly, as depicted in FIG. 12A, the substrate 510 is provided, and theplurality of first concaves 510 a, the plurality of second concaves 510b and the plurality of third concaves 510 c on the substrate 510,wherein a depth of the first concaves 510 a is greater than a depth ofthe second concaves 510 b, and the depth of the second concaves 510 b isgreater than a depth of the third concaves 510 c. The depth of the firstconcaves 510 a, the depth of the second concaves 510 b and the depth ofthe third concaves 510 c are respectively equal or close to a depth ofthe first light emitting diode chips 520, the depth of the second lightemitting diode chips 530 and the depth of the third light emitting diodechips 54. Next, as depicted in FIG. 12B, the plurality of first lightemitting diode chips 520, such as the red light emitting diode chips, ismoved onto the substrate 510. Now, a portion of the first light emittingdiode chips 520 go into the first concaves 510 a, a portion of the firstlight emitting diode chips 520 go into the second concaves 510 b andprotrudes out of a surface 512 of the substrate 510, and a portion ofthe first light emitting diode chips 520 go into the third concaves 510c and protrudes out of a surface 512 of the substrate 510.

As depicted in FIG. 12C, the first light emitting diode chips 520protruded out of the surface 512 of the substrate 510 are removed. Then,as depicted in FIG. 12D, the plurality of second light emitting diodechips 530, such as the blue light emitting diode chips, is moved ontothe substrate 510. Now, a portion of the second light emitting diodechips 530 go into the second concaves 510 b, a portion of the secondlight emitting diode chips 530 go into the third concaves 510 c andprotrudes out of a surface 512 of the substrate 510. Next, as depictedin FIG. 12E, the second light emitting diode chips 530 protruded out ofthe surface 512 of the substrate 510 are removed. Then, as depicted inFIG. 12, the plurality of second light emitting diode chips 540, such asthe green light emitting diode chips, is moved onto the substrate 510.Now, the second light emitting diode chips 540 go into the thirdconcaves 510 c, and at least partially completed the fabrication of thelight emitting element 500. As mentioned above, by using the thicknessesof the light emitting diode chips and the depths of the concavescorresponded thereof as a basis of assembly accuracy of the lightemitting diode chips, the assembly accuracy may be enhanced and therebyenhances the throughput.

FIG. 13A to FIG. 13E are flow diagrams illustrating a fabricating methodof a light emitting element according to yet another exemplaryembodiment. Firstly, as depicted in FIG. 13A, a plurality of lightemitting diode chip groups 50 is provided. In FIG. 13A, one lightemitting diode chip group 50 is schematically illustrated, wherein eachlight emitting diode chip group 50 includes a carrier board 52, a firstlight emitting diode chips 620, a second light emitting diode chips 630and a third light emitting diode chips 640. The first light emittingdiode chips 620, the second light emitting diode chips 630 and the thirdlight emitting diode chips 640 respectively are a red light emittingdiode chip, a blue light emitting diode chip and a green light emittingdiode chip and are disposed on the carrier board 52. A shape of thefirst light emitting diode chips 620 is different from a shape of thesecond light emitting diode chips 630 and a shape of the third lightemitting diode chips 640.

As depicted in FIG. 13B, a substrate 610 is provided, and as depicted inFIG. 13C, a plurality of concave groups 60 (one concave group 60 isschematically illustrated in FIG. 13C) is formed on the substrate 610,wherein each concave group 60 includes a first concave 610 a, a secondconcave 610 b and a third concaves 610 c, a shape of the first concave610 a is corresponded to the shape of the first light emitting diodechip 620, a shape of the second concave 610 b is corresponded to theshape of the second light emitting diode chips 630, and a shape of thethird concave 610 c is corresponded to the shape of the third lightemitting diode chip 640. Next, as depicted in FIG. 13D, the lightemitting diode chip group 60 is moved onto the substrate 610, so thatthe first light emitting diode chip 620, the second light emitting diodechip 630 and the third light emitting diode chip 640 of the lightemitting diode chip group 50 respectively go into the first concave 610a, the second concave 610 b and the third concave 610 c of the concavegroup 60. After the first light emitting diode chip 620, the secondlight emitting diode chip 630 and the third light emitting diode chip640 at the light emitting diode chip group 50 respectively go into thefirst concave 610 a, the second concave 610 b and the third concave 610c of the concave group 60, as depicted in FIG. 13E, the carrier board 52of the light emitting diode chip group 50 is removed, and at leastpartially completed the fabrication of the light emitting element 600.

FIG. 14 is a top view of the light emitting element of FIG. 13E.Referring to FIG. 13E and FIG. 14, in the present embodiment, the firstconcave 610 a, the second concave 610 b and the third concave 610 c openat a surface 612 of the substrate 610. A method for forming the firstconcaves 610 a, the second concaves 610 b and the third concaves 610 cincludes the following steps. A profile (illustrated as a rectangle inFIG. 14) of the first concave 610 a at the surface 612 is correspondedto a profile (illustrated as a rectangle in FIG. 14) of a cross sectionof the first light emitting diode chip 620. A profile (illustrated as atriangle in FIG. 14) of the second concave 610 b at the surface 612 iscorresponded to a profile (illustrated as a triangle in FIG. 14) of across section of the second light emitting diode chip 630 and differentfrom the profile of the first concave 610 a at the surface 612. Aprofile (illustrated as a circle in FIG. 14) of the third concave 610 cat the surface 612 is corresponded to a profile (illustrated as a circlein FIG. 14) of a cross section of the third light emitting diode chip640 and different from the profile of the first concave 610 a at thesurface 612 and the profile of the second concave 610 b at the surface612. As a result, the first concave 610 a, the second concave 610 b andthe third concave 610 c may respectively have different shapescorresponded to the first light emitting diode chip 620, the secondlight emitting diode chip 630 and the third light emitting diode chip640.

In addition, as depicted in FIG. 13A, a thickness of the first lightemitting diode chip 620 is greater than a thickness of the second lightemitting diode chip 630 and a thickness of the third light emittingdiode chip 640. Correspondingly, the method for forming the concavegroup 60 includes the following steps. As depicted in FIG. 13C, a depthof the first concave 610 a equals to the thickness of the first lightemitting diode chip 620, a depth of the second concave 610 b equals tothe thickness of the second light emitting diode chip 630, and a depthof the third concave 610 c equals to the thickness of the third lightemitting diode chip 640. As such, the first concave 610 a, the secondconcave 610 b and the third concave 610 c, in addition to havingdifferent profiles so as to differ in shapes as depicted in FIG. 14, mayalso be differ in depths as depicted in FIG. 13C, such that each lightemitting diode chip group 50 has a directivity to be used as a basis ofassembly accuracy of the light emitting diode chips.

In summary, the first concaves and the second concaves of differentvolumes are formed on the substrate, and the volume of the first lightemitting diode chips and the volume of the second light emitting diodechips are respectively corresponded to the volume of the first concavesand the volume of the second concaves. As a result, when the first lightemitting diode chips and the second light emitting diode chips are movedonto the substrate, the first light emitting diode chips selectively gointo the first concaves corresponded thereof, and the second lightemitting diode chips selectively go into the second concavescorresponded thereof, so as to enable the first light emitting diodechips and the second light emitting diode chips to quickly and correctlybe assembled onto the substrate via the automatic alignment, and therebyeffectively enhance the throughput of the light emitting element.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of thedisclosed embodiments without departing from the scope or spirit of thedisclosure. In view of the foregoing, it is intended that the disclosurecover modifications and variations of this disclosure provided they fallwithin the scope of the following claims and their equivalents.

What is claimed is:
 1. A fabricating method of a light emitting elementcomprising: providing a substrate; forming a plurality of first concavesand a plurality of second concaves on the substrate, wherein a volume ofeach first concave is different from a volume of each second concave;providing a plurality of first light emitting diode chips and aplurality of second light emitting diode chips, wherein a volume of eachfirst light emitting diode chip is corresponded to the volume of eachfirst concave, and a volume of each second light emitting diode chip iscorresponded to the volume of each second concave; and moving the firstlight emitting diode chips onto the substrate so that the first lightemitting diode chips go into the first concaves, and moving the secondlight emitting diode chips onto the substrate so that the second lightemitting diode chips go into the first concaves.
 2. The fabricatingmethod of the light emitting element as recited in claim 1, wherein ashape of each first concave is different from a shape of each secondconcave.
 3. The fabricating method of the light emitting element asrecited in claim 1 further comprising: forming a plurality of thirdconcaves on the substrate, wherein a volume of each third concave isdifferent from the volume of each first concave and the volume of eachsecond concave; providing a plurality of third light emitting diodechips, wherein a volume of each third light emitting diode chip iscorresponded to a volume of each third concave; and moving the thirdlight emitting diode chips onto the substrate so that the third lightemitting diode chips go into the third concaves.
 4. The fabricatingmethod of the light emitting element as recited in claim 1, wherein thestep of forming the first concaves comprises: making an inner wall ofeach first concave into a cambered surface.
 5. The fabricating method ofthe light emitting element as recited in claim 1 further comprising:forming a reflective layer at an inner wall of each first concave. 6.The fabricating method of the light emitting element as recited in claim5 further comprising: disposing an electrode within each first concave;and electrically connecting the reflective layer to the electrode. 7.The fabricating method of the light emitting element as recited in claim1 further comprising: disposing a first electrode at a first regionwithin each first concave, wherein a shape of the first region iscorresponded to a shape of a positive electrode terminal of each firstlight emitting diode chip; and disposing a second electrode at a secondregion within each first concave, wherein the shape of the first regionis different from a shape of the second region, and the shape of thesecond region is corresponded to a shape of a negative electrodeterminal of each first light emitting diode chip.
 8. The fabricatingmethod of the light emitting element as recited in claim 1 furthercomprising: disposing positive and negative electrodes of periodicallystaggered arrangement within each first concave, wherein when thepositive and negative electrodes on each first light emitting diode chipgo into each first concave, the positive and negative electrodes areadapted to respectively contact the positive and negative electrodes ofperiodically staggered arrangement.
 9. The fabricating method of thelight emitting element as recited in claim 1 further comprising:disposing a positive electrode pad and a negative electrode pad at asurface of each first light emitting diode chip, wherein one of thepositive electrode pad and the negative electrode pad is located at thegeometric center of the surface; disposing a first electrode at thegeometric center of a bottom surface of each first concave; anddisposing a second electrode at the bottom surface of each firstconcave, wherein the second electrode appears to be in ring-shaped andsymmetrically surrounds the first electrode, and a distance between thefirst electrode and the second electrode equals to a distance betweenthe positive electrode pad and the negative electrode pad.
 10. Thefabricating method of the light emitting element as recited in claim 1,wherein each first concave and each second concave open at a surface ofthe substrate, and the steps for forming the first concaves and thesecond concaves comprise: enabling a profile of each first concave atthe surface to correspond to a profile of a cross section of each firstlight emitting diode chip; and enabling a profile of each second concaveat the surface to correspond to a profile of a cross section of eachsecond light emitting diode chip and to be different from the profile ofeach first concave at the surface.
 11. The fabricating method of thelight emitting element as recited in claim 1, wherein when moving thefirst light emitting diode chips onto the substrate, a portion of thefirst light emitting diode chips go into the first concaves, and anotherportion of the first light emitting diode chips go into the secondconcaves and protrude out of a surface of the substrate, and thefabricating method of the light emitting element further comprises:removing the first light emitting diode chips protruded out of thesurface.
 12. The fabricating method of the light emitting element asrecited in claim 1 further comprising: forming a first electrode withineach first concave; and forming a second electrode within each secondconcave, wherein a material of the first electrode is different from amaterial of the second electrode, the first electrode is adapted to besoldered with a first soldering temperature, and the second electrode isadapted to be soldered with a second soldering temperature.
 13. Thefabricating method of the light emitting element as recited in claim 1further comprising: forming optical microstructures on each first lightemitting diode chip and on each second light emitting diode chip. 14.The fabricating method of the light emitting element as recited in claim1, wherein each first concave has an opening terminal and a bottomsurface, and the step of forming the first concaves comprises: graduallyshrinking each first concave from the opening terminal toward to thebottom surface.
 15. A light emitting element comprising: a substratehaving a plurality of first concaves and a plurality of second concaves,wherein a volume of each first concave is different from a volume ofeach second concave; a plurality of first light emitting diode chips,wherein a volume of each first light emitting diode chip is correspondedto the volume of each first concave, and the first light emitting diodechips are located within the first concaves; and a plurality of secondlight emitting diode chips, wherein a volume of each second lightemitting diode chip is corresponded to the volume of each secondconcave, and the second light emitting diode chips are located withinthe second concaves.
 16. The light emitting element as recited in claim15, wherein a shape of each first concave is different from a shape ofeach second concave.
 17. The light emitting element as recited in claim16 further comprising a plurality of third light emitting diode chips,wherein the substrate further has a plurality of third concaves, avolume of each third concave is different from the volume of each firstconcave and the volume of each second concave, a volume of each thirdlight emitting diode chip is corresponded to the volume of each thirdconcave, and the third light emitting diode chips are located within thethird concaves.
 18. The light emitting element as recited in claim 15,wherein an inner wall of each first concave is a cambered surface. 19.The light emitting element as recited in claim 15, wherein an inner wallof each first concave has a reflective layer thereon.
 20. The lightemitting element as recited in claim 19, wherein each first concave hasan electrode therewithin, and the reflective layer is electricallyconnected to the electrode.
 21. The light emitting element as recited inclaim 15, wherein a first region within each first concave has a firstelectrode, a shape of the first region is corresponded to a shape of apositive electrode terminal of each first light emitting diode chip, thefirst electrode is electrically connected to the positive electrodeterminal, a second region within each first concave has a secondelectrode, the shape of the first region is different from a shape ofthe second region, the shape of the second region is corresponded to ashape of a negative electrode terminal of each first light emittingdiode chip, and the second electrode is electrically connected to thenegative electrode terminal.
 22. The light emitting element as recitedin claim 15, wherein a surface of each first light emitting diode chiphas a positive electrode pad and a negative electrode pad, one of thepositive electrode pad and the negative electrode pad is located at thegeometric center of the surface, the geometric center of a bottomsurface of each first concave has a first electrode and a secondelectrode, the second electrode appears to be in ring-shaped andsymmetrically surrounds the first electrode, a distance between thefirst electrode and the second electrode equals to a distance betweenthe positive electrode pad and the negative electrode pad, the firstelectrode is electrically connected to one of the positive electrode padand the negative electrode pad, and the second electrode is electricallyconnected to another one of the positive electrode pad and the negativeelectrode pad.
 23. The light emitting element as recited in claim 15,wherein each first concave and each second concave open at a surface ofthe substrate, a profile of each first concave at the surface iscorresponded to a profile of a cross section of each first lightemitting diode chip, and a profile of each second concave at the surfaceis corresponded to a profile of a cross section of each second lightemitting diode chip and different from the profile of each first concaveat the surface.
 24. The light emitting element as recited in claim 15,wherein each first concave has a first electrode therewithin, eachsecond concave has a second electrode therewithin, a material of thefirst electrode is different from a material of the second electrode,the first electrode is adapted to be soldered with a first solderingtemperature, and the second electrode is adapted to be soldered with asecond soldering temperature.
 25. The light emitting element as recitedin claim 15, wherein each first light emitting diode chip and the eachsecond light emitting diode chip have optical microstructures thereon.26. The light emitting element as recited in claim 15, wherein eachfirst concave has an opening terminal and a bottom surface, and eachfirst concave gradually shrinks from the opening terminal toward to thebottom surface.